反应详情

温度

-78 °C

4-Oxo-piperidine-1,3-dicarboxylic acid 1-tert-butyl ester 3-ethyl ester (30.9 g, 114 mmol) was dissolved in CH2Cl2 (800 mL). DIPEA (48.7 mL, 285 mmol) was added, and the reaction mixture was cooled to −78° C. A sol. of Tf2O (24.4 mL, 148 mmol) in CH2Cl2 (25 mL) was added slowly, while maintaining the temperature at −78° C. The mixture was stirred for 30 min at −78° C. The mixture was allowed to warm to rt, and aq. 10% Na2CO3 (400 mL) and ice were added. The layers were separated and the aq. layer was extracted with CH2Cl2 (2×). The combined org. layers were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (heptane→EtOAc/heptane 25:75) yielded the title compound (44.0 g, 91%). LC-MS: tR=1.05 min; ES+: 404.44.

1. temperaturewhile maintaining the temperature at −78° C
2. temperatureto warm to rt
3. customThe layers were separated
4. extractionthe aq. layer was extracted with CH2Cl2 (2×)
5. dry with materiallayers were dried over MgSO4
6. filtrationfiltered
7. customthe solvents were removed under reduced pressure
8. customPurification of the residue by FC (heptane→EtOAc/heptane 25:75)